THIS IS A RUSH TRANSCRIPT. THIS COPY MAY NOT BE IN ITS FINAL FORM AND MAY BE UPDATED.

SOLEDAD O'BRIEN, CNN ANCHOR: Good evening, everybody. I'm Soledad O'Brien. Tonight: an investigation into the bridge collapse that happened right here in Minneapolis. What went wrong? What larger questions does the tragedy raise about the state of our nation's infrastructure?

(BEGIN VIDEOTAPE)

O'BRIEN (voice-over): It happened in an instant.

UNIDENTIFIED FEMALE: The road was just disappearing underneath of us.

UNIDENTIFIED MALE: The bridge started shaking. And then it was a complete freefall.

O'BRIEN: A bridge tumbles down.

UNIDENTIFIED MALE: Well, the bridge is gone.

UNIDENTIFIED MALE: I thought I was dead. I literally thought I was dead.

O'BRIEN: For years, we have been warned, our country's infrastructure is falling apart, streets exploding, levees breaking, aging power grids failing, roads collapsing.

Is our nation on a road to ruin?

(END VIDEOTAPE)

O'BRIEN: We begin tonight with the latest on the catastrophe.

Five people are now confirmed dead. At least 100 others were injured. Now, so far searchers have only been able to check out 12 of the 60 cars that are submerged in the murky Mississippi water. The NTSB says it's going to examine a second videotape of the collapse, and tomorrow President Bush will visit the disaster site.

Now, on the bottom of your television screen is a ticker listing some of the thousands of the bridges throughout the United States that are in need of repair. And, at CNN.com, you can see a state-by-state list of all bridges similar in design to the one that collapsed right here in Minneapolis.

The U.S. Department of Transportation wants those bridges inspected immediately.

And now, as we look down at the wreckage from this rooftop on the Bridgewater Lofts, the overwhelming question is how could it have fallen so suddenly with no warning at all.

CNN investigative correspondent Drew Griffin has been digging into that question for us. And what he's found really only adds to the mystery.

(BEGIN VIDEOTAPE)

DREW GRIFFIN, CNN INVESTIGATIVE CORRESPONDENT (voice-over): It struck so fast with such force, even those who were on the bridge had no idea what was happening.

UNIDENTIFIED MALE: It felt like the concrete just disappeared and you were just falling, just a freefall all the way down. And, when we hit, we hit hard.

GRIFFIN: This surveillance camera video captures an event that bridge experts say would be almost impossible if they did not see it themselves.

TED GALAMBOS, STRUCTURAL ENGINEER: I couldn't believe it. This just does not happen. It's not within my rational universe.

GRIFFIN: For 40 years, the 35-W bridge carries up to 140,000 cars a day across the Mississippi River. Then, in seconds, and without any warning, it falls 64 feet into the river below.

Dr. Ted Galambos is one of the foremost bridge engineers in the world. He's studied bridge failures most of his professional life. He cannot explain this one.

(on camera): This looked like what?

GALAMBOS: Sudden death.

GRIFFIN (voice-over): Or was it? The Minnesota Department of Transportation has begun releasing its own bridge inspection reports for bridge 9340 that show this bridge may not have suffered sudden death, more of a long-term illness.

DAN DORGAN, MINNESOTA DEPARTMENT OF TRANSPORTATION: In 1990, it was classified as a structurally deficient bridge.

GRIFFIN: By 1993, the bridge was undergoing yearly inspections. In 2001, six years ago, due to concerns about fatigue cracking, the University of Minnesota conducted an extensive monitoring of the bridge, even placing strain gauges, like these, to measure if the bridge was weakening.

All of these warnings, all of the problems, all judged not enough to stop the flow of traffic. Minnesota had decided it would not replace the bridge until the year 2020. The latest inspection just months ago concluded the bridge was safe. DORGAN: Obviously, something went terribly wrong.

GRIFFIN: At a news conference Thursday, Dan Dorgan, the state's top engineer, had to admit the inspection process itself had failed.

QUESTION: You're in charge of all these other bridges that have been inspected the same way. Are you a nervous man right here?

GRIFFIN (on camera): Sixty miles up the Mississippi River here in Minnesota, in the town of Saint Cloud, is this bridge, the DeSoto Bridge. It is almost built the same exact style as the bridge that fell in Minneapolis. And it's from here, underneath, you can see the super-steel substructure.

(voice-over): Underneath the DeSoto Bridge, we found classic signs of age, corrosion, rust, pieces of concrete crumbling. But, as bad as it looks, University of Minnesota's civil engineering head, Dr. Robert Ballerini, says steel beams just don't break. They bend.

DR. ROBERT BALLERINI, UNIVERSITY OF MINNESOTA CIVIL ENGINEERING DEPARTMENT: If I take a piece of chalk and I snap it, I will have no evidence whatsoever that it's about to fail. Steel, on the other hand, before it fails, it has to go through a plastic deformation. You will see it with your eyes actually bend. And that gives warning, hey, something is wrong here. I'm sick. Fix me.

GRIFFIN (on camera): And that is what has engineers baffled. They say, even if there was a stress fracture in one or even two of these big beams, the bridge would have tilted, maybe rocked a little, and eventually pulled itself into the water.

But that's not what happened. This entire structure would have had to collapse at the same time, meaning multiple beams would have to have multiple cracks almost simultaneously.

BALLERINI: It collapsed relatively all at the same time, and I haven't even begun to think of what could have caused that sudden failure over the whole span of the bridge.

GRIFFIN (voice-over): What lies ahead is a reconstruction of the parts of the skeleton that are left. Chunks of the broken bridge will be brought up from the river, resembled, and searched piece by piece for the fatal wound that years of inspections failed to find.

(END VIDEOTAPE)

GRIFFIN: And certainly that inspection report is very detailed, showing inspection after inspection showing multiple problems on this bridge. This bridge was really sick.

In 2006, a 50-page report detailed all the cracks, the bruises and the bumps, and came up with one basic conclusion, that eventual replacement of this entire structure would be preferable. O'BRIEN: Now, Drew, the NTSB, which rarely speculates, as you well know, came out today early on and said they're focusing on the south end of the bridge. What do they know at this early juncture?

GALAMBOS: They know that, at the south end of the bridge, the actually bridge separated, titled there. It didn't all collapse there. It shifted.

And so what they are going to look at is to see, was there was separation? And, in fact, in this report, it shows some separation that they tried to Band-Aid. And that's what I think we have here. We have a bridge that had multiple problems that was Band-Aided together.

And whether by political will or a budgetary decision, the decision was made to keep putting those Band-Aids on this bridge until 2020, when they would decide to replace it.

O'BRIEN: How long will an investigation take? How long before we know exactly what the cause was?

GRIFFIN: Usually, it takes a year. The engineer, who was 78, in our report says, I hope I'm alive when that report comes out.

However, the NTSB, as you said, rarely comes out with any kind of inclination. They seem to be moving very quickly towards the south end of this bridge.

O'BRIEN: It is. That's very unusual for them.

Drew Griffin, thank you very much. Appreciate it.

Still ahead this evening: Crumbling bridges aren't even the half of it. Why is so much of our nation's infrastructure falling apart?

And the shock of cheating death.

(BEGIN VIDEO CLIP)

SARAH MUNDY, SURVIVOR: I remember that woman in front of me in the silver -- I just remember when she was going down in front of me. And I just remember hoping that, oh, that she was OK, too.

(END VIDEO CLIP)

O'BRIEN: Next, the lucky survivors and the heroic rescuers tell us their stories.

(COMMERCIAL BREAK)

O'BRIEN: The bridge plunged so swiftly and so suddenly that drivers navigating the bumper-to-bumper rush-hour traffic had no warning. So many of those who survived are still in shock, and many who witnessed the collapse or tried to help still cannot believe just what happened here.

Tonight, they share their stories of survival and common purpose in the wake of the disaster.

(BEGIN VIDEOTAPE)

UNIDENTIFIED MALE: The concrete just disappeared and you were just falling, just a freefall all the way down. And, when we hit, we hit hard.

O'BRIEN: Caught in a catastrophe.

UNIDENTIFIED FEMALE: We were falling, literally falling.

O'BRIEN: Amid tragedy, close calls.

MUNDY: I just remember, when she was going down in front of me. And I just remember hoping that, oh, that she was OK, too. I don't know why.

O'BRIEN: And calls to courage.

(on camera): Days later, as it starts sinking in about how dangerous it was, and, honestly look behind you, how massive that collapse was...

CAPT. SHANNA HANSON, MINNEAPOLIS FIRE DEPARTMENT: It doesn't even have to be days later.

O'BRIEN (voice-over): In an instant, a bridge in the heartland of America disappears.

For Captain Charlie Leekley, it was a front-row ticket to an unthinkable disaster.

CAPT. CHARLIE LEEKLEY, EYEWITNESS: I saw a lot of people that didn't have a chance. It's a 65-foot drop, at least.

O'BRIEN: Captain Leekley was taking a group of 48 tourists out on a paddleboat ride when the 35-West bridge collapsed right in front of him.

(on camera): What did it sound like?

LEEKLEY: Oh, it would be hard to describe. Like -- it displaced a considerable amount of water very quickly. And it came raining down like a waterfall of ash -- no, not ash, but dust and debris.

O'BRIEN (voice-over): When the bridge fell apart, shock was the first reaction, rescue the next almost instant response.

HANSON: When we were in the river, almost all of the stuff was moving somewhat.

O'BRIEN: Shanna Hanson, a captain at Minneapolis Fire Station 14, was off duty when the bridge collapsed. With just a yellow rope and a life jacket, she plunged into the murky and dangerous waters of the Mississippi to search for survivors.

O'BRIEN (on camera): It wasn't a scary scene for you personally?

HANSON: Firefighters are trained to do this. It's not -- it's something that that is our office. And it's what we're supposed to be able to handle.

MUNDY: It's getting better, but, for the last couple days, it just constantly replays.

O'BRIEN: Sarah Mundy was on the bridge as it crumbled right before her eyes.

MUNDY: Well, I was traveling northbound, and, all of a sudden, I see the rock crumble from below the car in front of me, and just dust everywhere. And then the car in front of me disappears.

O'BRIEN: She soon felt her car dropping, too.

MUNDY: The worst part was not knowing -- the anticipation of what I was going to hit at the bottom.

O'BRIEN: Sarah Mundy didn't tumble into the river. Her car was left teetering at the edge of a broken segment of the bridge, precarious, to be sure, but remarkably good fortune.

MUNDY: I can't believe that I made it out OK with some bruised ribs and scratches.

O'BRIEN (on camera): A few more feet and you would have been right there?

MUNDY: Yes.

(END VIDEOTAPE)

O'BRIEN: Joining us now, one of the first rescuers on the scene, Sergeant E.T. Nelson of the Minneapolis Police Department. He pulled dozens of people out of the wreckage.

Thanks for talking to us, sir. We certainly appreciate it.

How quickly were you able to get to the scene?

SERGEANT E.T. NELSON, MINNESOTA POLICE DEPARTMENT: Within three or four minutes of the initial call.

O'BRIEN: And what was it like? Some people have described it as silent. Others say people were screaming. What did you hear?

NELSON: There were people screaming. It seemed like pockets of survivors here and there. Some were verbal. Some were not. It was a scene of total devastation.

O'BRIEN: Some people, like Sarah Mundy, who we just saw in that piece, remarkably, showed me a scratch that she had. And she sort of bruised herself. Other people, you could see their cars just crushed, and not even to mention those who ended up, unfortunately, in the river.

The bulk of the people who you were helping, where were they on the span?

NELSON: The bulk of the people I encountered were on the span of the bridge, which was -- actually had fallen into the river.

O'BRIEN: What were you able to do for them?

NELSON: We made our way to that span using the bridge wreckage as a ladder, so to speak, and did a quick triage on those individuals, assessing their injuries, and then evacuated them from that span, as it's somewhat -- it is not very stable.

O'BRIEN: Were there people you could not help?

NELSON: Yes, there were.

O'BRIEN: We heard from a firefighter who said, when you're a firefighter, you go into rescue mode, and it's not scary.

Were you scared, with that structure and everything crumbling around you?

NELSON: I agree with what the firefighter said. At the time of arrival, you assess the situation. You refer to your training. You have a job to do, and you do the job. That's what's expected of you.

And, once it's all said and done and over, you look back on it, and it's not especially a place that I would be likely to return to.

O'BRIEN: When it's all said and done, and you literally look back over it, can you believe what we're seeing here?

NELSON: It is somewhat unbelievable, the amount of devastation in a matter of seconds, turning a commute, rush-hour commute, into one of total chaos.

O'BRIEN: More than 40 cars, they still haven't even checked on the Mississippi there, under the water, submerged.

O'BRIEN: When we come back in just a moment, beyond Minneapolis, because what happened here could happen anywhere in the country, a nation of thousands of crumbling bridges and dangerous dams.

And who's to blame? You might start with the people you send to Congress. They're the ones who spend our money. We will take a look at that.

Stay with us.

(COMMERCIAL BREAK)

O'BRIEN: We had been warned for decades that a massive hurricane would overwhelm New Orleans' levees, and it did. More than 1,800 people died. We're still being warned about the crumbling levees around Sacramento, California. Thousands of homes are at risk, while hundreds more are being constructed. Is that a disaster that is waiting to happen?

And a construction firm sounded the alarm back in 1999 about problems with the bolts used to secure several two-ton concrete ceiling panels in Boston's famous Big Dig tunnel. Some of those panels fell onto a car last year and killed a woman.

We have been warned for decades about decaying bridges, but it took the catastrophic failure right behind me for officials in Washington, D.C., to take action. Transportation Secretary Mary Peters has ordered the Federal Highway Administration to offer help to all 50 states so they can complete inspections of bridges like the one here.

But is this a case of too little government action too late?

(BEGIN VIDEOTAPE)

O'BRIEN (voice-over): Very few of us expect a bridge to collapse when we're driving over it. And most of us don't plan for a horrific explosion in the heart of Manhattan while rushing to catch a train. But that's exactly what's happened in the space of a few short weeks.

UNIDENTIFIED FEMALE: You guys got to keep moving.

O'BRIEN: It turns out a who may not be to blame, but a what, the infrastructure.

RAE ZIMMERMAN, NEW YORK UNIVERSITY: Each event is becoming so much more catastrophic. That's more of an opinion, rather than based on hard data, but, you know, things like that steam explosion and the Minneapolis bridge, we don't see.

O'BRIEN: We have been warned about the bridges. A 2005 report by the American Society of Civil Engineers listed more than 590,000 of them in the United States, many at the heart of the nation's interstate highway system. Nearly a third, more than 160,000, were classified as structurally deficient.

ANDREW COATES, AMERICAN SOCIETY OF CIVIL ENGINEERS: That means that we have gotten to a point where we can expect to expend significant amounts of money on these bridges.

O'BRIEN: There have been warnings over the years. In one of the most infamous such events in American history, a suspension bridge over the Ohio River, connecting West Virginia to Ohio, collapsed in December 1967; 46 people died.

Or this spectacular crash. A bridge in Tacoma, Washington, sways four months after it was built in 1940. It had a nickname, "Galloping Gertie." And more, a 100-feet section of Interstate 95 near Greenwich, Connecticut, the Mianus River Bridge, collapsed in the summer of 1983. Three people died.

UNIDENTIFIED MALE: The accident was first reported to state police just before...

O'BRIEN: In 1987, two spans of a bridge on Interstate 90 in Upstate New York collapsed; 10 people died. Just last month, an interstate highway bridge in Northern California went down. Fortunately, no one was killed. And the traffic just keeps getting heavier and heavier.

COATES: As traffic increases, weights of truck increases, the cumulative damage to some of these bridges, fatigue and otherwise, is kind of rising at a high level.

O'BRIEN: At a high level as well are concerns about those tangled water, steam and sewer lines that are buried beneath the streets of the nation's largest cities. This explosion, adjacent to New York City's Grand Central Station in early summer, was from a steam pipe that was 83 years old. It was just one tiny section of a grid of more than 100 miles, and ruptures of water mains are so common, they aren't even big news anymore.

In fact, all over the country, the fundamentals that make up the nation's infrastructure are in poor shape. Take dams. According to the Federal Emergency Management Agency, of the 79,500 dams in the United States, about a third pose a high or significant hazard.

ZIMMERMAN: We're sorting that out, and, yes, there is a measure of hazard, and they have emergency action plans for a lot of those dams.

O'BRIEN: What about our aging railroad system? The Federal Railroad Administration charts every rail accident in the nation. In 2006, more than a third of those accidents were caused by track defects. All in all, it sounds like a mess.

ZIMMERMAN: All of these problems should not cast a pall over infrastructure. It should rather redirect our attention to, how can we make it better?

O'BRIEN: The Civil Engineers Association says, in an ideal world, where government money is no object, it would take about $9.5 billion a year over the next 20 years -- that adds up to $188 billion -- to fix it all. That, they concede, is unlikely to happen.

COATES: Deferring repairs are just going to become more and more costly, so it's going to be a question of catching up, and the longer we wait, the bigger of price tag will be.

(END VIDEOTAPE)

O'BRIEN: Stephen Flynn is the author of "The Edge of Disaster: Rebuilding a Resilient Nation," a shocking indictment of how we as a nation aren't doing what needs to be done to keep our communities safe. We spoke earlier today.

(BEGIN VIDEOTAPE)

O'BRIEN: You're the guy who said this was going to happen. Your worst-case scenario was right.

STEPHEN FLYNN, SENIOR FELLOW IN NATIONAL SECURITY STUDIES, COUNCIL ON FOREIGN RELATIONS: Well, certainly, what we're dealing with here is the fact that we have a lot of infrastructure in this country, and we haven't been taking care of it very well. And it's aging, and not gracefully. And so it's inevitable at some point. It's going to break down on us, and, of course, here, tragically, in such a catastrophic way.

O'BRIEN: At the end of the day, is it just about the money? It's expensive to fix crumbling infrastructure.

FLYNN: Yes, it has a lot to do with the lack of money.

But, of course, what makes us not spend is that we have taken it for granted. You know, most of this infrastructure was built by our parents and our grandparents, great-grandparents. So, infrastructure is just like our bodies. It starts to age and get more frail. And, if you don't invest in keeping it up, it's going to break.

We used to have world-class infrastructure. I mean, the rest of the world would look at us and say, some day, they hope to have the kind of modern society we have. If you want to see world-class infrastructure, you have to go overseas now, because this kind of infrastructure was built a long time ago, without the kind of -- and, today, we're not providing the kind of care it needs to keep servicing us, never mind to be able to pass this legacy on to our children and our grandchildren.

O'BRIEN: But certainly you're not predicting that this wrenched bridge, which we can see from just here, that is going to be a scene repeated in city after city after city country across this country, right?

FLYNN: We're going to see failures. They are going to take lives and cause real disruption to our lives.

Also, this vulnerability, this brittleness of our society, makes us far more attractive for terrorists, potentially, to hit us, because a little blow can go a very long ways. The fact is, we need to be more resilient, and we need to make investment in our infrastructure, this legacy we have inherited, a real national priority.

(END VIDEOTAPE)

O'BRIEN: Stephen Flynn will be back with us later in our broadcast.

But up next: While bridges decay, Congress spends hundreds of millions of dollars on pet projects. What's wrong with our nation's priorities?

Then later, the bridges aren't the only weak link we have been warned about. What's being done about the 3,000 dams that have been classified as unsafe?

(COMMERCIAL BREAK)

ERICA HILL, NEWS ANCHOR: I'm Erica Hill at the CNN Center in Atlanta, ROAD TO RUIN continues in a moment, but first, here's a look at tonight's headlines.

First, President Bush today, urging Congress to pass a bill making it easier for the government to eavesdrop on foreign terror suspects abroad, but negotiations between the White House and lawmakers over the issue broke down a short while ago. The president's push follows action by a special court earlier this year that restricted the eavesdropping ability of the intelligence community.

Iraqi prime minister, Nuri al Maliki, welcoming back the National Soccer Team today after its return from the Asian Cup Championship win, but the regular Friday holy day curfew put a dampener on any large-scale celebrations in Baghdad.

In Los Angeles, police say dogs belonging to Ving Rhames (INAUDIBLE) mauled a caretaker at the actor's home, today. The man's body was found on the lawn, four dogs were taken into custody. Rhames was not home at the time.

And stocks taking a dive today, the Dow plummeted 280 points, the Nasdaq lost 65, the S&P was down over 39 points.

I'm Erica Hill. Those are your headlines at this hour. Stay with CNN, ROAD TO RUIN with Soledad O'Brien continues in just a few minutes.

(COMMERCIAL BREAK)

O'BRIEN: Welcome back, everybody. I'm Soledad O'Brien in Minneapolis. Tonight, the bridge collapse, what may have caused it and what does it say about our nation's infrastructure? We're also hearing stories of survival. Like this one, Bill Wagner, who was driving a UPS truck across the bridge when it fell and he fell with it. He suffered three broken ribs and a collapsed lung, but he's talking with us tonight.

Bill, nice to see you. How are you feeling?

BILL WAGNER, UPS DRIVER, MN BRIDGE SURVIVOR: I feel sore.

O'BRIEN: Yeah, I bet you do. But you look good.

WAGNER: Well, I appreciate that.

O'BRIEN: Tell me when you first realized that there was something very bad happening to the bridge. You were driving across with the truck.

WAGNER: Right, and it was kind of surreal, the bridge started shaking. I mean, I lived out in L.A. for a while, and I know what an earthquake was, and it was just like an earthquake. It just started shaking and before I knew it, the bridge kind of started swaying side to side, and next thing I remember was I was looking straight ahead and I saw girders, and then it suddenly dawned on me that if I'm looking at girders, I'm on part of the bridge falling, and I'm looking underneath the bridge.

O'BRIEN: I noticed before when you were sitting there, you were looking at our shot...

WAGNER: I was.

O'BRIEN: Which is a strange angle, and you probably haven't seen it a lot. Describe what you're thinking about when you see it from here.

WAGNER: I really don't like to look at it, to be honest with you. O just -- just the thought of it brings back bad memories. I don't know if you know this, but that Tasty Truck out there, I worked for Tasty, and the guy, Paul, that died in that truck, I worked with him for five years. In fact, he had just passed me and we waved to each other. And next thing I knew, you know, that whole truck was on fire, so it hit me pretty hard.

O'BRIEN: How were you able to get out?

WAGNER: Well, I tell you, I was very fortunate that the side of the freeway that collapsed in, it took my truck, and the reason I was fortunate was because there was a busload of kids in front of me, and if it wouldn't have fallen off like that, I would have hit those kids.

O'BRIEN: They missed the edge by what it looks like feet.

WAGNER: And I was right behind them.

O'BRIEN: If your truck had hit them, you would have pushed the busload of children through that crevice.

WAGNER: That's right. So, I was kind of happy that I fell, but I got to tell you, you know, when I was falling -- and I fell about 30 feet -- when I was falling, the only thing that ran through my mind was, you're going to die. And I don't know how to explain it, other than the fact that I didn't feel sad, I didn't feel afraid, I just felt at peace.

O'BRIEN: There were lots of people on that bridge pulling people out, some of the people who were survivors said they couldn't believe people were running to help, because they were so desperate to get off the bridge and away from the accident.

WAGNER: Well, the interesting thing was is the kids that were on that bus, prior to entering that bridge, they were all given me the toot the horn deal, and I did, and the guy that was next to me, after Paul had passed me, he was laughing, because I had pulled the horn for them. And after I got out of my truck -- because when I was in my truck and I was upside down, I smacked my head on the top, it sounded like rain inside my truck and then I realized diesel fuel was coming all over inside the truck.

So, my first instinct was, you know, diesel fuel doesn't burn, it's got to be really hot to burn diesel, but I thought if it gets on the engine, it could start a fire, or even electrical. So the first thing I thought of doing was turning off the ignition and shutting the engine down. By that point, I didn't even feel like I was hurt, I didn't feel like my ribs were broke, nothing. I just knew I had to get out of there.

O'BRIEN: It's amazing to think you were able to save yourself, but also think of those kids in that bus. We've certainly seen lots of pictures of them. Bill Wagner, thanks for talking to us. I know it's tough to see it from this angle, so we certainly appreciate you doing that.

WAGNER: Yeah, well, you know, actually, the toughest thing was, as big as I am, I couldn't help anybody. You know, that's really what I wanted to do, but I just couldn't. And I was just really grateful that the people that were there were helping not only me, but everybody else and taking the time to do it.

O'BRIEN: Rescuers really did a tremendous job.

WAGNER: Yeah, they were great and I don't think they're getting enough attention.

O'BRIEN: Well, you've given it to them tonight, sir.

WAGNER: I hope so. That's why I wanted to show up.

O'BRIEN: Well, thanks for talking to us. We certainly appreciate it.

WAGNER: Appreciate it, thank you.

O'BRIEN: Still ahead, when a bridge fails, a community suffers clearly, but do you know that there are more than 3,000 American's dams that are classified as unsafe? And if they fail, well, the flooding could be catastrophic over huge areas. So, what's being done to fix them? We'll take a look. (COMMERCIAL BREAK)

O'BRIEN: The bridge tragedy, here in Minneapolis, exposed the appalling condition, not only of America's bridges, but of the very infrastructure that we depend on every day, like roads, and pipelines, and dams, too. There are more than 80,000 dams in this country, and when it bursts, the disaster is catastrophic.

CNN's Ted Rowlands has our report.

(BEGIN VIDEOTAPE)

TED ROWLANDS, CNN CORRESPONDENT (voice-over): This Hollywood version of a dam break from the movie "Earthquake" may seem far- fetched, but over the years there has been several horrific real-life disasters caused by failed dams.

ANNOUNCER: The water broke over the top.

ROWLANDS: The first sign that huge dams might bring huge problems, came with a string of disasters in the 1970s. This amazing sequence of photos shows the collapse of the Teton Dam in Idaho, 14 people died downstream, towns inundated with water. Hundreds more died in other dam catastrophes in Pennsylvania, Georgia, and West Virginia. Now more than 30 years later, aging dams have engineers worried another round of failures is possible.

LARRY ROTH, American SOC OF CIVIL ENGINEERS: Some of these dams are ticking time bombs and unfortunately you can't just look at the structure and determine that it's potentially going to fail imminently.

ROWLANDS: In the last two years, there have been more than 20 significant dam failures in the United States, seven people killed just last year when the aging Ka Loko Dam gave way on the Hawaii island of Kauai.

In 2005, a park in Missouri was leveled by a wall of water after a sudden dam failure, fortunately the park was almost empty and nobody was killed.

According to the Society of Civil Engineers, of the 83,000-plus registered dams in the United States, more than 3,300 are classified as unsafe, 825 of them are in Ohio, 725 in Pennsylvania, and 193 in New Jersey.

KEITH FERGUSON, CIVIL ENGINEER: And a failure can occur within minutes to hours worth of time under the worst circumstance.

ROWLANDS: Colorado civil engineer, Keith Ferguson, is a member of the Association of State Dam Safety Officials. He says the problem is pretty simple -- dams are built to last about 50 years, and many of them are getting very old.

FERGUSON: Yes, the constant cycling of loads on these structures and the way they age, yeah they're getting worse with time. ROWLANDS (on camera): This dam in Colorado is owned and maintained by the federal government, but most dams in the country are privately owned, meaning it's up to individual states to make sure those dams are safe.

The problem, according to experts, is that some states are not doing a very good job.

(voice-over): Take New York, the state oversees 1,906 dams with only eight full-time employees. Maine has one inspector responsible for over 800 dams. In Texas, seven inspectors are responsible for more than 7,000 dams. And then there's the state of Alabama, which has more than 2,000 dams, but doesn't have any inspectors at all.

ROTH: Our report card identified that there are 3,500 unsafe dams in the United States. Now, when I hear the word "unsafe," I don't know what it means to you, but to me it ought to be a red flag that something needs to be done.

ROWLANDS: Fixing the problem means lots of money. Congress is currently considering allocating more than there $200 million for dam reconstruction. Experts, however, say that would just be a drop in the bucket. The American Society of Civil Engineers estimates at least $10 billion is needed to solve a problem, which, as dams get older continues to get worse.

(END VIDEOTAPE)

O'BRIEN: That was Ted Rowland's reporting for us.

Back with us tonight, Stephen Flynn an expert on protecting our critical infrastructure.

Stephen, if you had to give a grade to America's dams, what grade would they give?

STEPHEN FLYNN, AUTHOR, THE EDGE OF DISASTER: Well, I don't have to give one, the American Society of Civil Engineers are the nation's top engineers. Look at all infrastructure, 15 categories, bridges came out the second best, dams got a "D" and the trends are not good at all.

O'BRIEN: You know, in the piece, Ted was talking a lot about the lack of oversight at the various dams across our nation. Is it the problem that the lack of oversight is the issue? Or is it a money problem?

FLYNN: They both go together, of course, there's not even money to inspect the dams. People don't know there's problems, so we didn't invest in fixing them.

But what we're doing is we're crowding people near where these dams are, and when a dam breaks, it's a wall of water, people drown and die. These are models of engineering, as is so much of the infrastructure across this country, but you have to maintain it. You can't just be -- ignore it, you have to invest in it. O'BRIEN: And yet, it seems to me at least, it's kind of an invisible problem. I mean, you don't really talk about the dams, and certainly not the state that they're in.

FLYNN: It's a crazy thing. It used to be a point of pride Americans had as a nation that we built the best infrastructure in the world. There was almost a competion going on in the world. Now the world is looking at this country and seeing things like this, seeing the flood system fail in Katrina. What does it say about this country? It says we essentially become like adolescents, we don't pay attention to the things around us.

O'BRIEN: At the same time, as we both know, and a dam, I can tell you it's expensive to fix, it's not just the will of the people, it's actual dollars and cents.

FLYNN: Dollars and cents and the jobs to fix these things are good jobs, so it goes back into the economy. We get benefits, and the infrastructure is essentially for keeping the quality of our life up to speed.

You know, with roads, 3.5 billion hours are wasted of people sitting in traffic. That comes out that economists estimate $65 billion a year wasted sitting in traffic. There's an economic cost to having our infrastructure in the bad state it is.

O'BRIEN: Well, clearly we can just look out and see not just the economic cost, but the cost in lives. There are 40, approximately, vehicles that are still in the Mississippi that they can't even inspect to see if there are people still inside of them. Do you think this is a big enough wake-up call, not just for the bridges, but the dams and all the infrastructure, too?

FLYNN: I pray it is. I hope that Americans don't go back to sleep or think this is an isolated event. Our best engineering minds, we have the fact, the infrastructure is getting old, is not being maintained and we're demanding more from it. This is a formula for disaster.

O'BRIEN: Coming up next, the disaster as it happened. Witnesses and rescuers, the people who made it out alive. We have their stories. Stay with us.

(COMMERCIAL BREAK)

O'BRIEN: Each person who made it out of the bridge collapse has a survival story, but none has a story quite like it the man you're about to meet. Here's Gary Tuchman.

(BEGIN VIDEOTAPE) GARY TUCHMAN, CNN CORRESPONDENT (voice-over): Among the vehicles remaining on the wreckage on the destroyed Minneapolis bridge is this blue minivan. Its driver slammed on the brakes as the roadway collapsed, but the van wasn't going to stop on time, so the driver, Marcelo Cruz, took evasionive action.

(on camera): And in the last second, you swerved into the wall?

MARCELO CRUZ, SURVIVOR: Yeah, that's what I did.

TUCHMAN: And that saved your life?

CRUZ: Yeah.

TUCHMAN (voice-over): His close call, harrowing, but maybe even more incredible -- because Marcelo Cruz is a paraplegic. He was by himself in the van and couldn't get out as the bridge crumbled and as fire started to rage.

(on camera): How many cars did you see go into the water?

CRUZ: Twenty, something like that.

TUCHMAN (voice-over): Marcelo has a special hand brake and can normally get in and out of his van with a ramp, but his vehicle had stopped on a severe decline.

(on camera): So if you would have gotten out of your van down the ramp -- the road is pointing...

CRUZ: By myself.

TUCHMAN: ...you would have ended up in the river?

CRUZ: Yeah, with my wheelchair.

TUCHMAN: With your wheelchair, you would have rolled into the river?

CRUZ: Yeah.

TUCHMAN (voice-over): While he waited helplessly, he heard a woman screaming.

(on camera): What was she saying?

CRUZ: Just "help me, somebody help me." That's stressful, because you want to do something, and you cannot do anything.

TUCHMAN (voice-over): He doesn't know what happened to the woman, but finally help came for him.

(on camera): So, who got you out?

CRUZ: There were a couple people that helped me.

TUCHMAN: Do you know who they were?

CRUZ: No, probably they were working there -- workers.

TUCHMAN: Probably pretty grateful to them?

CRUZ: Yeah.

There is my car.

TUCHMAN (voice-over): Marcelo keeps seeing his van on the TV as he watches coverage OF the disaster with his mother, who was stunned when her son called her from the bridge.

IGNACIA CRUZ, MARCELO'S MOTHER (through translator): I was very scared, I was crying because I couldn't control myself. He was in so much danger.

TUCHMAN: The 26-year-old Mexican immigrant has suffered some back pain from the collapse, but because he no longer has his van, he had no way to go to the emergency room, so we were happy to drive him.

Marcelo was left paralyzed after being shot and critically wounded by an unknown assailant seven years ago. So, he's no stranger to the hospitals. He was relieved the doctors here told him these injuries are not serious. He feels he's a very lucky man.

(on camera): How has this changed your life?

CRUZ: A lot, you know, because, now, I feel like I had to tell people, you know, they had to live every day, you know, like it's going to be the last day, you know, of their life. You know, they have to enjoy it, really enjoy, you know, every day.

TUCHMAN (voice-over): This, coming from a man who says he's had two near-death experiences.

(END VIDEOTAPE)

O'BRIEN: That was Gary Tuchman reporting for us.

And while the tragedy here in Minneapolis raises lots of questions about what we are and really aren't doing to maintain our nation's infrastructure, it also shows us the true nature of the human spirit when suddenly a person is forced to fight for survival.

(BEGIN VIDEOTAPE)

UNIDENTIFIED MALE: The bridge on 35W has collapsed.

UNIDENTIFIED MALE: The first thing I thought about when I was falling is: Oh my god, I'm going to die right before my first kid is going to be born.

UNIDENTIFIED MALE: After it had collapsed, it was eerily quiet for at least five minutes, probably even more, before we even heard a siren in the distance. UNIDENTIFIED MALE: And we couldn't tell if the cries were for help are from people that are trapped.

UNIDENTIFIED MALE: I realized this school bus was next to me. And me and a couple of other guys went over and started lifting the kids off the bridge.

UNIDENTIFIED MALE: They were all screaming, they were all thinking they were going to die, even when we were safe, they were just -- they wanted their parents.

UNIDENTIFIED MALE: Everybody was crying and -- for their mom, and they want to go home.

UNIDENTIFIED MALE: People were stunned, people where crying, people were scared. I don't know how this could happen.

UNIDENTIFIED MALE: I'm not going to confirm fatalities. There are a number of fatalities.

UNIDENTIFIED MALE: The injuries were all pretty much consistent with blunt-force trauma.

UNIDENTIFIED MALE: We should all be grateful for the time we have here on this planet.

UNIDENTIFIED FEMALE: And then the biggest relief and scariest thing all together, that it was -- it was really close, it was really close.

UNIDENTIFIED MALE: Obviously, this is a catastrophe of historic proportions for Minnesota.

UNIDENTIFIED MALE: In the horror of this incident, there's a silver lining that shines through, and that is the goodness of Minnesotans.

(END VIDEOTAPE)

O'BRIEN: Sorrow and fear, and heroism. We're back with Stephen Flynn our expert on protecting our critical infrastructure, once again.

It's interesting to see to me, Stephen, to see, certainly today, as we've been reporting, you see the survivors coming to terms with the fact they made it out of that, which seems unsurvivable. You see the parents whose children have survived the bus that is this close to a gaping hole, and you think, well, wouldn't it be a loss if a lesson wasn't learned from this?

FLYNN: It really would be a tragedy, truly compounding on this tragedy. You know, democracy works only if our citizens tell elected officials what priorities we want. Every day people need to insist on their elected officials to know what's going on, and what are you doing about it? They need to hold our politicians accountable for setting priorities and (INAUDIBLE) the resources to make sure this kind of tragedy is not repeated in communities around this country.

O'BRIEN: A hundred and eighty-eight billion dollars is one estimate of what it would cost, just for the bridges part, not the dams or anything else we've been talking about. If the money was there, would that be enough? Or is it political will and more on top of it?

FLYNN: Let me put that number in perspective. The total amount of money the federal government is providing the states to inspect dams -- $22 million is what we spend every hour in Iraq. This country spends a lot to make ourselves safe and secure, on national security. We need to think about how we can to invest that here, as well.

We have the resources. We're the wealthiest country in the world. We have a gross domestic product of $14.2 trillion. We're at our wealthiest as a nation. Not investing in the infrastructure is a crime.

But also there's a security rationale for doing it. The more resilient we are as a society, the less attractive it is for adversaries to hit us, here.

You know, the president tells us time and again, the only way to win the war on terror is to go overseas. Well, part of the job has to be here at home as well, and we get a benefit about investing in our infrastructure and making it resilient, we prevent tragedies like this from happening, as well.

O'BRIEN: Stephen Flynn, thank you again for being our guest throughout our hour.

Before we go, you should about a CNN initiative that puts you, the viewer, in a position to impact your world. If you want to know how you can help in the aftermath of this bridge collapse, you can go right to cnn.com/impact.

I'm Soledad O'Brien, that you for much for joining us and goodnight.

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